Printing telegraph exchange system



Sept. 21, 1937. J. c. FRICKE PRINTING TELEGRAPH EXCHANGE SYSTEM Filed July 21, 1950 /TNVENTOR i|AcKsou c. FR BY ICKE Patented Sept. 21, 1937 I umrsn srn'res PATENT OFFICE PRINTING TELEGRAPH EXCHANGE SYSTEM ration of Delaware Application July 21, 1930, Serial No. 469,393

19 Claims.

This invention relates to printing telegraph exchange systems and more particularly to a printing telegraph exchange system in which the lines extending between the central station and the subscribers stations are normally open to direct current.

Heretofore in printing telegraph exchange practice there have been systems in which the lines extending between the central station and the subscribers stations or subscribers lines are normally open to direct current, while the lines are closed, when intercommunication between the central station and the subscribers station is to take place, by manual means at the subscribers station. Such systems required an attendant operator at each subscribers station for the purpose of closing the subscribers line to direct current whenever the central station desired to communicate with the subscribers station. In the present system, the subscribers lines are normally open to direct current, but in place of the manual means at each subscribers station for closing the line to direct current, means under control of the control station are provided for closing the line whenever intercommunication between the stations is desired. Once the subscribers line has been closed, the printing telegraph apparatus at the subscribers station is automatically conditioned for the reception of 3 messages, thus making it unnecessary for the subscribers operator to be in attendance whenever it is desired to transmit a message from the central station to the subscribers station.

One of the principal objects of the present invention is to eliminate in a printing telegraph exchange system the'current drain which ordinarily takes place over the lines extending between the central station and the several subscribers stations.

Another object is to provide means at the central station for automatically closing the line to direct current and for automatically conditioning the printing telegraph apparatus at each of the stations for intercommunication.

In carrying out the objects of the invention, an alternating current relay is associated with the line at each of the subscribers stations and a source of alternating superimposed on direct r0 current is provided at the central station, and when these sources are impressed upon the line, the alternating relay at the connected subscribers station is operated, closing the line to direct current and conditioning the telegraph apparatus for intercommunication.

One embodiment of the present invention is shown in the accompanying drawing which represents diagrammatically the various circuits, relays and other equipment arranged in three groups which are respectively designated 0, the operating table, C, the concentration board, and 5 S, the subscribers station.

At station S a signaling button I is grounded on one side through a resistance 2 and on the other side connects with the line 3. An alternating current relay l is adapted to respond to a 10 revertive signal which results from plugging in a cord tip at the concentration board C. Two pairs of contacts 5 and 6 are closed by the actuation of relay l, and after the latter has been tripped by a signal, it remains mechanically l5 locked, until released by an associated slow operating restoring relay 7. A condenser 8 is placed in the circuit of the relay 4 to make the latter responsive only to A. C. signals and to prevent current drain from battery 2! during idle periods. A retard coil 9 is placed in the circuit of the relay 7 to assist in slowing up its operation. A slow release relay It is included in the communication circuit between two printers. It is adapted to hold open the restoring relay circuit and also 25 to maintain a closed printer motor circuit during the transmission of messages. When a plug is removed from its jack at the concentration board the slow release relay Ill is deenergized and restores the subscribers station to normal or idle condition.

The printer motor H is shown in a circuit l2 which connects with any suitable A. C. or D. C. power source. The printer magnet I3 is in series with the printer keyboard circuits l4.

At the concentration board C of the central ofiice the subscribers line 3 is shown connected through an adjustable resistance l5 with a monitor jack l6 and thence to a regular jack I1. The line circuit is then conducted to one coil of a line relay l8, through the contact springs IQ of a slow release relay 20 and thence to a grounded battery 2!.

A line lamp 22 connects through the resistance 23 with the grounded battery 24 and also with the contact point 25, adapted to be connected to a grounded armature of relay l8. Relay I8 is controlled by relay 2!].

A locking circuit 26 for relay l8 includes a 50 winding thereon, one terminal of which connects with its own locking contacts 21. This circuit also includes the breaker contacts 28 under the control of relay 20.

A cord-tip circuit 29 connects any jack at the concentration board C with suitable instruments at the operating table 0. A supervisory lamp circuit 30 includes two lamps 3|, one at the concentration board C and the other at the operating table 0.

The cord-sleeve circuit 51 is conducted through the winding of a relay 32 which has the following functions, (1) to put battery potential on the line relay 33, (2) to complete the operating circuit for the printer motor 34, (3) to close a circuit for revertive signalling to the subscribers station, and (4) to prepare a locking circuit for the relay which serves momentarily to transmit the revertive signal and afterwards maintains a closed circuit between the operating table printer-keyboard 35 and the cord-tip circuit 29.

The revertive signalling circuit 37 has impressed upon it both alternating and direct current sources 38 and 39 respectively. The line relay 33 is provided with a biasing circuit 40. Its armature circuit receives potential from the battery M which is conducted to the printer magnets 42 and also to the coil of a supervisory relay 43. The circuit for relay 43 is not completed, however, unless the operator pushes the button 44 to 5 signal the concentration board operator that the message transmission has been completed. In doing this, the supervisory relay is actuated to open the supervisory lamp circuit 30. The line relay 33, the printer magnets 42, and the transmitter 36 are normally disconnected from the loop section 29, but are connected thereto upon the operation of ring and trip relay 35.

The operation of this invention will now be explained. It will be assumed that a message is tobe transmitted from station S to the central oflice O. The subscriber depresses the push button I thus grounding the line relay circuit which may be traced from battery 2| through the contact springs IQ of relay 25, through the operating winding of line relay I 8, through the short-circuited contact springs of jacks I1 and I6 respectively and thence through resistance I5 and line 3 to push button I which is grounded through the resistance 2. The line relay I8 operates to establish a monitor line lamp circuit which may be traced from battery 24 through the resistance 23, lamp22, to ground through the armature and contact 25 of relay I8. This lamp is lighted to signal the operator at the concentration board. Another pair of contacts 2?, of the line relay I8 operateto ground a locking circuit through this relay, current being supplied from the battery 2| through the break contacts 28 of relay 20 and.

through the conductor 26 which includes the locking winding of relay I8.

Upon seeing the lighted line lamp, the supervisor inserts in the line jack I! a cord plug associated with an idle printer. The plug-tip 48 breaks the circuit through the line relay l8 and the plug sleeve completes a circuit through the winding of the slow release relay 20. This circuit may be traced from battery 2I through the winding of relay 20, through the jack sleeve I'I, the'plug sleeve and the cord circuit 51, and the relay winding 32 to ground. The slow release relay 20 and cord circuit relay 32 both operate, the former opening the circuits to the line relay winding I8, restoring that relay to normal and extinguishing the line lamp 22; the latter applying direct current potential to the printer motor 34 and also to the line relay 33 and the transmitting keyboard 36. This latter circuit, however, is not completed through the line 3 until relay 35 operates to draw its armature against contact 5I. Previous to this, a revertive signalling circuit upon which both alternating and direct current sources 38 and 39 respectively are superimposed, is established by relay 32. This circuit may be traced through the conductor 31, contacts, one of the windings of relay 35, contact 41 and armature of said relay, cord-tip circuit 29, the tip thereof 48, jack contact 49, line 3, condenser 8, relay contacts and alternating current relay 4 to ground.

As soon as this relay 4 is actuated, contacts are made between the pairs of springs 5 and 6 respectively. This allows the direct current to follow through the circuit just described as far as the station-S-terminal of line 3 and thence through contact 5 to winding of relay II] from which it continues through the printer magnet I3 and keyboard I4 to ground.

As the left hand armature 58 of relay III starts to pull up it is momentarily grounded through a make-before-break spring combination 59. This has the effect of accelerating the operation of relay Ill since the inductive resistance of the printer magnet I3 is by-passecl. At the same time relay 35 is energized drawing its right-hand armature against the contact 5|. This completes the circuit from the operating table keyboard 36 to the line. Furthermore, a locking circuit is established through relay 35, originating at the battery 52 and passing through the locking contacts 53, winding 54, contact 45 of relay 32 and the armature 55 thereof which is grounded. The breaking of contact 41 interrupts the circuit whereon alternating and direct current sources 38 and 39 respectively are superimposed. At the subscribers station the relays 4 and I are arranged for cooperation so that when relay 4 operates its armau ture is mechanically locked by a latch 58. This locking arrangement holds the contacts 5 and 6 in the make position until the locking arrangement is tripped by the relay 1.

The operation of relay I5 closes the circuit I2 from a source of power through the printer motor II. In order to obviate any chance of the relay I operating and breaking the line circuit prematurely, the retard coil 9 is placed in series with its winding so that before it can pull up the slow release relay I0 operates and cuts off the battery 56 from relay 1.

The circuit is now in condition for printer operation and it will be understood that the printer signals do not release the slow release relay I9 because there is no interruption in the flow of current through traflic transmission of sufficient duration to allow said relay I II to release.

To terminate a call, the operator at the central oflices depresses the bush'button 44 thus operating and locking up a supervisory relay 43 and extinguishing supervisory lamps 3I. The concentration board supervisor withdraws the plug from the jack I! which restores all circuits to normal at stations 0, C and S respectively. The slow release relay 20 at the concentration board is timed to allow the slow release relay III at the subscribers station to release first supplying current from battery 56 to relay I and operating the relay. This in turn restores contacts 5 and 6 to their open position. During the restoration operation, the circuit to relay 4 is broken by relay I so that a capacity kick from the line cannot operate it. When contacts 6 have been opened, relay 1 deenergizes, the slow release relay 20 at the concentration board now releases and all circuits are restored to normal. It is evident that the operation of the system is the same as that just described when a call -is initiated at the central ofiice, except that in this case the line relay I8 and the supervisory lamp 22 at the concentration board are not operated.

What is claimed is:

1. 'A telegraph system comprising a first station, a second station, a line normally open to direct current connecting said stations, telegraph apparatus at each of said stations normally disconnected from said line, a source of alternating current at said first station, an alternating current relay at said second station, responsive to the connection of said source to said line, for connecting the telegraph apparatus at said second station to said line, and means responsive to the operation of the alternating current relay for connecting the telegraph apparatus at said first station to said line.

2. A printing telegraph system comprising a first station, a second station, a line normally open to direct current connecting said stations, a printer at each of said stations normally disconnected from said line, a motor for operating each of said printers, means under control of said first station for closing said line to direct current for connecting the printer at each of said stations to said line and for starting the printer motor at each of said stations.

3. A printing telegraph system comprising a first station, a second station, a line normally open to direct current connecting said stations, a printer at each of said stations normally disconnected from said line, an operating motor associated with each of said printers, a source of alternating current at said first station, an alternating current relay at said second station responsive to current from said source when the latter is connected to said line for connecting the printer at said second station to said line, means thereafter operable for starting the printer motor at said second station, and means for starting the printer motor at said first station prior to the connection of the printer at said second station to said line.

4. A printing telegraph system comprising a first station, a second station, a line normally open to direct current connecting said stations, a printer at each of said stations normally disconnected from said line, an operating motor for each of said printers, a relay at said first station, an alternating current relay at said second station, responsive to current from said source when the latter is connected to said line, for connecting the printer at said second station to said line, and means responsive thereto for starting the motor at the second station and for operating said first station relay to connect the printer thereat to said line.

5. A printing telegraph exchange system comprising a first station, a second station, a line connecting said stations, a printer at each of said stations normally disconnected from said line, a source of alternating current at said first station, an alternating current relay at said second station, responsive to current from said source when the latter is connected to said line, for connecting said printers to said line, and means for disconnecting each of said printers from said line.

6. A printing telegraph system comprising a central station, a source of alternating current at said station, a sub-station, a line normally open to direct current connecting said stations, a printer normally disconnected from said line, motor control relay and printer motor at said sub-station, means controlled by said central station for closing said line to direct current and for connecting said printer and motor control relay to said line, and means thereafter operable for actuating said motor control relay to close the operating circuit of said printer motor.

'7. A printing telegraph system comprising a central station, a sub-station, a line normally open to direct current connecting said stations, a printer and a motor control relay normally disconnected from said line, and a motor for operating said printer at said sub-station, means controlled by said central station for closing said line to direct current and for connecting said printer and motor control relay to said line, and means thereafter operable for actuating said motor control relay to close-the operating cir cult of said motor.

8. A printing telegraph exchange system comprising a central station, a sub-station, a line normally open to direct current connecting said stations, said sub-station having a printer and a motor control relay normally disconnected from said line, a motor for operating said printer and an alternating current relay for conditioning said line to permit the flow of direct current and for connecting said printer and motor control relay to said line, means at said central station for operating said alternating current relay, and means thereafter operable for actuating said motor control relay to start said motor.

9. A printing telegraph exchange system comprising a central station, a source of alternating current superimposed upon a source of direct current at said station, a sub-station, a line normally open to direct current connecting saidstations, said sub-station having a printer and a motor control relay normally disconnected from said line, a motor for operating said printer, an alternating current relay, responsive to alternating current from said source when the latter is connected to said line, for connecting said printer and motor control relay to said line, said motor control relay being responsive to direct current from said source, after the closure of said line to direct current, to start said printer motor.

10. A printing telegraph exchange system comprising a central station, a source of alternating current at said station, a sub-station, a line normally open to direct current connecting said stations, said sub-station having a printer and a motor control relay normally disconnected from said line, said motor control relay having one circuit through said printer and an additional bypass circuit, a motor for operating said printer,

a slow-operating restoring relay for re-opening said line to direct current, and an alternating current relay, associated with said line and operated by current from said source when the latter is connected to said line, for connecting said printer and said motor control relay to said line and for closing an operating circuit for said restoring relay, and means thereafter operable for energizing said motor control relay over said bypass circuit before the restoring relay is operated, whereupon said printer motor is started and the operation of said restoring relay is prevented.

11. A printing telegraph exchange system comprising a central station, a sub-station, a line normally open to direct current connecting said stations, said sub-station having a printer and a motor control relay normally disconnected from said line, a motor for operating said printer, and an alternating current relay operable from said central station for closing said line to direct 

